Centrifugal casting or coating system



July 19 1927. 1,636,228

A. W. GRAY CENTRIFUGAL CASTING 0R COATING SYSTEI Filed June 6, 1925 2 Shoots-Shoat 1 INVEN 0R A ATTORNEY 1,636.228 July 1 7- w. GRAY CENTRIFUGAL CASTING OR COATING SYSTEM Filed June 6. 1925 2 Sheets-Shoot 2 251 ATTORNEY ill Patented July 19, 1927.

UNITED STATES ARTHUR W. GRAY, OF MILFORD, DELAWARE.

CENTRIFUGAL CASTING OR COATING SYSTEM.

Application filed June 6,

My invention relates to apparatus for centrifugally distributing molten or liquid material on the interior of a rotating surface, as a mold, or for coating, covering or spraying an object disposed mteriorly of a mold or equivalent structure.

In accordance with my invention, an suitable molten or liquid material, as meta glass, enamel, or the like prior to introduction into a rotating structure is caused to assume an angular velocity that may be smaller, greater, or substantially equal to the angular velocity of the rotating structure.

Further in accordance with my invention, any suitable molten or liquid material, as aforesaid, is initially introduced into a rotating container or conduit suitably arran ed to cause the molten or liquid material quic 1y to assume substantially the same angular velocity as that of the container or conduit,

- Further in accordance with my invention, the interior surface of a rotating container F or conduit is provided with a longitudinally disposed rib or a plurality thereof for engagment with and a consequent propelling ac tion on the molten or liquid material.

My invention resides in apparatus and features of construction of the character hereinafter described and claimed.

For an understanding of my invention and for an illustration of some of the various forms in apparatus may take, reference is to be ha to the accompanying drawings, in

which:

Figure 1 is a vertical longitudinal section of my improved casting machine.

Fig. 2 is an end view of the mold.

Fig. 3 is an end view of the conduit.

Fig. 4 is a transverse section of the conduit on the line Jr- 1 of Fig. 1.

Fig. 5 illustrates a modification of the arrangement shown b Fig. 4.

Fig. 6 is a vertical longitudinal section of a modified type of casting machine.

Fig. 7 is a transverse section on the line 77 of Fig. 6.

Referring to Fig. 1, the base of my improved casting machine forms a support for a vertically extending standard 2 provided with an opening 3 receiving and rotatably supporting a suitable structure as a mold 5;, Although but one standard and one end of the mold is shown, it isto be understood that the base supports another similar stand- 1925. Serial 110. 85,301.

ard likewise provided with an opening for the reception andsupport of the mold. Adjacent one end, mold 4 is enlarged exteriorly as shown at 5 and is further enlarged at its extreme end to provide a depending flange 6. The enlar ed portion 5 is provided with a circum erentially extending groove 7 for the reception of the standard 2, the shoulders formed b the-groove resisting and preventing axial thrust of the mold in either direction. The standard at the far end of the base merely supports the mold 4 for rotative movement and is arranged to allow axial movement thereof in either direction. In this manner, free expansion and contraction of the mold is permitted without interfering with its rotation. As is well understood in the art, suitable anti-friction bearings (not shown.) may be arranged between the contacting surfaces of the standards 2 and the mold 4.

On its inner surface, mold, 4 may be provided with a suitable lining, as the sand or loam linin 7, placed in position by ordinary foundry methods. Or, a mixture of sand, clay, cement, and water known as slurry may be deposited centrifugally on the mold interior and subse uently hardened in any desired manner. hr, the lining may be omitted entirely and a chill mold of a type well known in the art may be utilized. If desired, one end of the mold may be partially closed by a.ring 7 which forms a wall for retaining one end of the casting 7 during solidification. Ring 7 may be provided with an inwardl extending portion 7 for a purpose hereinafter described.

Disposed on the base 1 at right angles to the axis of rotation of the mold 4 are the uide members 8, one of which may have a -section 9 for reception by the inclined recessed portion 10 of a frame 11 which is provided with a plurality of guide-ways 12. If desired, base 1 may be provided with a plurality of upwardly extending columns 13, one for each mold, and each provided with an additional guide-we. 14 in horizontal alignment with the guide-ways 12 for a purpose hereinafter described.

. idably disposed on the guide-ways 12 is a frame 15 havin upwardly extending standards 16 provide with openings 17 receivin and rotatably supporting a casing 18. no standard 16 is received between flanges 19 formed adjacent one end of the casing 18, whereby axial movement of the ms with res to the frame 15 is reven l. 7 As is 2:?1 understood in the :irt, suitable anti-friction bearings (not shown) may be arranged between the contacting surfaces of the standards 16 and casing 18.

In accordance with my invention, rotative movement imparted to the casing 18 is in turn transmitted to the mold 4, or'vice versa, in any desired manner, and as one arrange ment for so do' i the casing 18 at the end remote from thes 19 may be provided with a flange 20 for the rezgption of a pin 21, or a plurality thereof, pted to enter and be engagled by the sides of an open ended slot or ole 22, or a plurality thereof,

, formed in the flange 6 of the mold 4. For a purpose hereinafter described, a guard 23 may be disposed exteriorly of and partially surrounding the flanges 6 and 20.

The casing 18 may be rovided with a .suitable lining 24 as a re rectory material when substances at high temperature such as molten'metal are being cast. Casing 18 and its lining 24 form a conduit which may be conical to assist in impelling the molten or liquid material toward the mold and which further may be rovided with one or more inwardly e'xten ribs 25 shown in Fig/ 4 as extending radially thereof. If desired, ribs 25 ma be bent laterally as shown in Fig. 5 an such bending may be continued until the free ends thereof contact with the inner surface of lining 24 whereby a number of substantially c osed longitudinally extendingbotube-hke passa es are provided. It is to understood t t the rib structure or a whether extending radial] or bent later-1111?, as aforesaid may be rifled 1. e. bent spir at any suitable pitch. Further, 1t 18 to be understood that the rib structure may be omitted entirely leaving the mner.surface of the lining 24 substantially smooth. At

times, it may be desirable to cause deflection of the entering stream of moltenvor liquid material toward the inner wall of the conduit in which case a cone 26 .maybe ar-..

ranged within the lining 24 and secured to the rib structure 25 in any suitable manner as b 27 formed therein and into whic the cone is fitted.

If desired, adjacent the entrance of mold 4 a plug 28 may be fitted agalnst enlarged portions 29 of ribs 25 and held in engagement therewith in an suitable manner. Flange 30 of the plug with theportion 7" of ringv 7" forms a restricted, curved path so that floating impurities, or the like, 1n the molten material will be tra andprevented from entering the mo Plug 28 1s rovided with an opening 31 for a purpose hereinafter described.

Mounted on fraine 15 adjacent one end of the casing 18 is the penis 32 comprising a casing 33 enclosing suitable mateportion thereof,

1,ese,aae

rial 34 shaped to provide a funnel 35 and a passage 36, refractory material being preferable where materials having high temperatures are being cast. Passage 36 is provided with a pipe or similar member 37 both opening into a spout 39 disposed in the throat 40 of the casing. heating flame or other suitable gas may be admitted through funnel 35 or pipe 37, preferably the latter, to heat the rotatable conduit or mold or to drive out the air and thereby prevent contamination of the material that is to be cast. Should the trap formed by plug 28 be closed, the h eatin or purifying gas ma ass through ho e 31 into the mold an t ere perform the desired function. I

Pi 37 also functions as a valve for closing t e outlet of the funnel 35 thereby provi ing a bottom-pour hopper for the purpose of excluding slag, dross, or other impurities from passage 39.

The operation is as follows:

Assuming that the various parts are as illustrated in Fig. 1, rotary motion will be imparted either to the mold 4 or the casing 18, or to both if desired. Due to the frictional engagement of the arts and the pin and slot connection 21 and 22, the mold and casi 18 will rotate as a unit.

Mo ten' material entering through the funnel 35 will pass downward! and then through spout 39 and into t e rotating conduit where it engages the deflecting cone 26 which throws it outwardl against the interior wall of the conduit. 11 assin to the other end of the conduit, t e mo ten material quickly assumes substantially the same angular velocity as the conduit due artly to the fact that the ribs 25, or equivaent, tend to grip the same and prevent sli page with respect to the conduit walis. ereafter, the now whirling stream of molten material escapes through the restricted passage between the abutment's 7 and 30 and rapidly revolving and with .'a cylindrical-shape substantially the same as t e mold, comes into engagement therewith at substantially-the same angular velocity as that of the mold.

As soon as the casting is completed but while rotation is continuing, the conduit comprisi casin 18 and limng 24 ma be separated rom t e mold by movement a ong carrying the conduit and associated funnel A the frame 'alon structure may be moved from mold to mold alon the guide-ways 8 and when in position before an empty. mold the axis of retation of the conduit may be ali ed with the axis of rotation of the mold y sliding the short ide-way 14, a similar device ing positloned on the base in front of eachmold and functioning1 as a guide. However, it is to be understoo that my invention is not to 'be limited to a mold and conduit constructed as separate units, but if desired, both mold and conduit may be constructed as one unitary structure.

It is to be understood that in casting long objects, it may be desirable to feed molten material into both ends of the mold, and

under these circumstances, rotatable conduits and associated funnel structures of the type shown in Fi'g. 1. may be provided at each end of the mold.

Referring to Fig. 6, there is illustrated a casting machine espeelall suitable for mak- "ing long pipe and inclu es a rotatable eonduit inserted into a rotatable mold together with suitable apparatus for causing relative movement between the mold and conduit. In this machine a spout 50 for the introduction of molten or liquid material is shown as opening into a conduit 51, the material being supplied by any suitable structure, as a funnel and associated parts of the same general type as described aforesaid with respect to Fig. 1. Conduit 51 may be formed of any suitable material, such, for example, as was indicated with respect to the conduit 24 of Fig. 1, and includes a casing 51 which may be supported for rotative movement in any desired manner as by a frame 52 fixed to base 53 carrying a suitable number of rolls 54, for instance three, spaced substantially equidistantly circumferentially about the casing 51. Each roll is suitably supported forrotative movement on a shaft 55 extending into oppositely disposed bearings 56. A journal 57 flanged at 58 is secured to casing 51 and the outer peripheries of the several rolls extend into rictional engagement with the journal between the flanges. With'this arrangement, rotative movement imparted to one of the rolls as hereinafter described causes the rotation of the conduit 51 and at the same time prevents longitudinal movement of the conduit with respect to base 53.

Driving mechanism 'of any suitable character may be selected for imparting rotative movement to the conduit and combined rotative and axial movement to the mold. As shown, a bifurcated member 60 mounted on'base 53 supports a main shaft 61 carryin a pulley 62 driven by a suitable source 0 power not shown) Main shaft 61, provided with a clutch disk 63, receives and is directly to shaft 64 and thence to one of the rolls 54 for rotating conduit 51.

A frame 65 movable axially along base 53, as hereinafter described, is grooved at 66 for the reception of a guiding rib 66" on the base 53. Bearings 67 in frame 65 receive and rotatably support a hollow shaft 67 to which a pair of drive rolls 68 are rigidly secured. A slot 69 in shaft 64 receives a key 70, or a plurality thereof, suitably secured to the rotatable structure comprising shaft 67 and rolls 68. Rotatably mounted in suitable bearin s in the front extension 65' of frame 65 is t e shaft 71 carrying a pair of rolls 72 corresponding with rolls 68.

A pair of arms 73 pivoted to an u per portion of frame 65 extend laterally of see 53, each providing a .bearin 74 for receiving and rotatably supporting a shaft 75 carrying a pair of rolls 76 for exerting downward pressure on the mold to hold the same in frictional engagement with rolls 68 and 72, the pressure being derived in any suitable manner, as by weights 7 3 adj ustable on arms 73.

The mold 77, preferably of the type known in the art as a chill mold although provided, if desired, with any suitable lining, supports and guides the free end of condult 51 and is rovided adjacent'one end with de ending anges 7 8 between which are receive one each of the pairs of rolls 68, 72, and 76. The other and corresponding .group of rolls receives and supports the mold adjacent its other end. In.this manner, the mold is firmly secured to the frame 65 for axial movement therewith without interfering with its axial contraction and expansion. Furthermore, radial expansion of the mold does not interfere with its free rotation since each of the pressure rolls 76 is yieldingly held in engagement with the mo d periphery.

Frame 65 and the structure carried thereby may be moved axially in either direction with respect to the base 53 in any suitable manner. As shown, the frame is provided with a threaded-bore 79 for the reception of a threaded shaft 80 rotatably secured at one end to the frame 52. Adjacent its other end, shaft 80 is rovided with cars 81 and 82 of any suitab e diameter. cars 83 and 84 freely rotatable on main shaft 61 may be alternatel locked into engagement therewith as desire by manipulation of clutch lever 85 actuatin clutch 86 keyed to the shaft but longitu inally slidable thereon. If the iii) clutch is en ged with gear 83 rotation will be imparted lo threaded shaft 80 in one direction and the mold will be moved toward the left as shown in Fig. 6. Correspondin engagement of the clutch with gear 84 will rotate the threaded shaft in the reverse direction and move the mold in the opposite direction.

If desired, the mold may be moved at a greater speed in one direction, for instance, toward the right in Fig. 6. Any suitable mechanism may be provided for effecting this function as the intermediate gear 85 meshing with gears 82 and 84.

It is to be understood that the molten or liquid material is delivered from spout 50 into conduit 51 and distributed from the latter into the mold. Any suitable arrangement may be utilized for increasing the angular velocity of the material while in the conduit as the longitudinall extending ribs 86. It is likewise to be an erstood that the number of ribs may be varied to suit different conditions andthat they may be modified as suggested in connection with Fig. 1, i. e. bent laterally, as desired, or rifled. Further, it is to be understood that, if desired, a cone or equivalentstructure may be used to deflect the material into engagement with the inner surface of the conduit.

If necessary or desirable, a flanged plug 87 may be fitted against enlarged ends 88 of ribs 86" and held in engagement therewith in any suitable manner. Adjacent the plug flange, conduit 51 may be increased in diameter whereby the molten material is caused to pass through a restricted, curved path so that floating impurities in the molten material will be trapped and prevented from entering the mold. If desired,'a snap rin 89, or a plurality thereof, may be provide to scrape and clean the mold as the one moves with reference to the other.

The operation is as follows:

At the beginning of a casting or like operation, the mold will be positioned in its eatreme position toward the right as showmm Fig. 6. With clutch disk 64" locked to disk 63, shaft 64 will be in rotation and likewise the rolls 54 and 68 carried b the shaft, the rotative movement of the re ls being imparted respectively to the conduit and mold, lhereupon, after the molten or liquid material has begun to pour from spout 50 into conduit 51, clutch 86 will be thrown into engagement with gear 8 1 The material in passing through the con it has its angular velocity increased b the ribs or like structure. of molten material escapes through the restricted passage adjacent the flung: of plug 87 and rapidly revolving and wit substantially the'same as the mold comes into engagement therewith at substantially the same angular velocity as that of the mold.

Thereafter, t e now whirling stream a shape When clutch 86 was engaged with ar 83, rotary movement was imparted to t readed shaft 80, the result being that frame carrying the rolls 68, 72, and 76 in turn car ing the mold 77 began its journey axia y toward the left (Fig. 6). Due to the key and slot connection 69 and 70, this axial movement will not interfere with free rotative movement of the drive rolls 68.

When the mold has moved the desired distance toward the left (Fig. 6), a flow of molten or liquid material is discontinued, and at the proper time clutch 86 isthrown to its neutral position and disk 64 is disengaged from disk 63. Thereafter, whenthe material being cast has hardened to a desired extent, arms 73 are raised in any desired manner and the mold removed. An empty mold may now be placed on rolls 68 and 72 and arms 7 3 lowered into the position shown in Fig. 7. Engagement of clutch 86 with gear 84 will cause reverse rotation of threaded shaft 80 whereupon the new mold will be caused to slide over the casing 51 of the conduit into proper position for a new casting or like operation.

t is to be understood that the conduit and mold of Fig. 6 may be caused to rotate at the same or different angular velocities by properly choosing the diameters of the driving rolls and the portions of the mold and conduit engaged respectively by such rolls. Further, it is to be understood that in apparatus of the character disclosed in Fig. 1, the conduit and mold need not rotate at the same speed, for it is obvious that the driving or frictional engagement between the parts could be eliminated, and by using separate 7 driving mechanisms respectively for the mold and conduit, their respective speeds of rotation could be varied as desired.

Briefly stated, my invention as described aforesaid, is effective in theproduc-tion of -various articles, and particularly pipe, that is free of the defects usually existing in such articles when produced by rior art centrifugal casting machinery. Since the an ular velocity of the liquid material is su ntially the same as thatof the mold when'it comes into contact therewith, and is" of aubstantiall the same shape as the moldfthe hereto ore well-known tendency ofrepeated dropping back and splashing of the metal into a pool at the bottom of the mold is obviated. This droppin and splashing increase greatly the surface of hot metal exposed to the atmosphere within the mold, augment the abrasion of the mold linin if used, cause some of the falling meta to freeze as it drops and stir into the molten frozen drops and impurities.

Moreover, when the liquid cast is fed into the mold in accordance" with my invention, it is practical to rotate the mold at much higher speeds than has been the suspended in the liquid. Also,

noiseless practice heretofore. Increasing the speedof rotation in eliminating impuritles by] increasthe pressure under which t e liquid difies,-the increased angular velocity ofthe mold results in the production of sounder Al pugh I have described several of the embodiments of my invention withsome articularity, it is to be understood that such fiescri .tion is illustrative, and not limitivc in so ofmy inventionli 'turetobe In the applended claims, it shall be understood that t e term gas is employed in a eric' sense to inclu e a flame for warmmg the mold, or a gas of an kind (reducing, oxidizing or neutral;l any temperapassed throug the conduit and .the mold in the direction of flow for wash- I comprising a rotatable comprising a duit, and means for from 'the conduit while comp said conduit,

sumo substantially ing out the airand'suhstituting an atmosphere of the kind desired.

What I claim is: 1. Apparatus of the character described comprising a rotatable conduit "means for a stream of molten or liquid materialin said conduit, means for causing the material to assume substantially the same angular velocity as that of the conduit, and means for receiving the material from the conduit while in molten or liquid condition. 2. Apparatus of the character described conduit means for p a stream of molten or liquid material into said. conduit,means comp in for causing the material to asthe same angular velocity as that of-the conduit, and means for receiving the material from the conduit while in molten or liquid condition.

3. Apparatus of the character described rotatable conduit, means for asmg a stream of molten or liquid material mto said conduit, meam extending axially of the conduitand independently of centrifugal action to m the angular f the material. while in said conreceiving the material in molten or liquid velocitycondition.

1. Apparatus of the character described comprismg a rotatable conduit, means for o l 1 a stream of or ii uid material into said conduit,.means for eflectingthe material radially toward the inner-*surface of the conduit, means functioning independently of centrifugal action for increasing theangular velocity of the material while in said conduit, and means for receiving the material from the conduit while in molten or uid condition. a V

mu i: m 'i i,

an e con ui means for introducing a of molten or liquid material into. said conduit, and means functlonmg independently of centrifugal acas'sociated with said conduit for increasthe angular velocity of said material w e in said conduit and in engagement withthe inner surface thereof.

6. Apparatus of the character described comprising a rotatin troducing a stream 0 molten or liquid material into said conduit, means independent of centrifugal action associated with said conduit for increasin the an' lar velocity of said material whi e in sai conduit and in engagement with the inner surface thereof, said means comprising a rib disposed axially of the inner surface of the conduit,"and means for receiving the material from the conduit while in molten or liquid condition.

7. Apparatus of the character described comprising a rotating conduit, means for introducing a stream of molten or li uid material into said conduit, a hook-shape rib in said conduit disposed axially thereof for engaging said material to increase its angular velocity, and means for receiving the mate ial from the conduit while in molten or liquid condition.

8. Apparatusof the character described comprising a rotating conduit whose interior surface comprises a series of axially extending passages, means for introducing a stream of molten or liqluid material into said passages, and a rotatab e mold receiving said material after passage 9. Apparatus of the character described comprising a rotating conduit roviding a series of spiral passa exten ing axia 1y of the interior thereo means for mtroducing a stream of molten or liquid material into said passages, and a rotatable mold receiving said material after passage through said conduit.

10. Apparatus of the character described com rising a rotating conduit whose interior sur ace comprises a series of axially extend-. ing tube-like passages, means for mtroducing a stream of molten or liquid material into said assages, and a rotatable mold receiving said material after passage through said conduit.

11. Apparatus of the character described comprising a rotating conduit providing a series of spiral tube-like passages extending axially thereof, means or introducing a stream of molten or liquid material into said passages, and a 'rotatable mold receiving siaid material after passage through said conuit.

12. Apparatus of the character described comprising a rotating mold, and means for introducing a stream of-molten or liquid material into said mold comprising a rotatmg conduit having an inner conical surface divergu'n in the direction of flow therethrou h and a radial rib extending inwa ly and axial thereof.

mnpperams o the character described tion conduit, means for inthrough said conduit.

comprising a rotatin mold, means for introducing a stream of molten or ,liquid material into said mold comprisi a rotatin'g conduit havin an inner conica surface divergin in e direction'sof flow therethroug and means independent of centrifugal action associated with said conduit for increasing the angular velocity of said material while in said conduit and in engagement with the inner surface thereof.

l4. Apparatus of thefcharacter described comprising a rotating mold 'nd means for introducing a stream oft on or liquid material into said,mold comprising a rotating conduit havingan-inner conical surface diverging in the, direction of flow therethrough, said conduit being provided with a series of axially extending passages on its inner surface. 4 s

15. Apparatus of the character described comprising a rotating mold, and means for introducing a stream of molten or liquid material into said mold comprising a rotating conduit having an inner conical surface diverging in the direction of flow therethrough, said conduit being provided with a series of axially extending spiral passages on its inner surface.

16. Apparatus of the character described comprising a, conduit, means for introducing a stream of molten or liquid material into said conduit means for deflectin said material toward the inner wall of said conduit, means for rotatin said conduit at a speed suflicient to centri gally retain'the material in engagement with its interior surface, and a mold receivin the material from said conduit while in su stantially tube-like form.

17. Apparatus of the character described comprising a rotating conduit, means for introducing astream of molten or liquid material into said conduit, and means comprising a cone shaped member for deflectin said idnaterial toward the inner wall of sai conuit.

18. Apparatus of the character described comprising a rotating conduit, ineans for introducing a stream of molten or liquid material into said conduit, rib structure insaid conduit and extending axially thereof, and a deflecting cone supported by said rib structure 19 Centrifugal casting apparatus comprising a rotating mold, a rotating conduit in axial alignment therewith, means for passing molten material through said conduit and into said mold, and ineans ad'acent the junction of said conduit and mol preventing passage of impurities into said mold.

Q0. Centrifugal castin apparatus comprising a rotating mold, a rotating conduit in axial alignment therewith, means for ing molten material throu said conduit and into said molil. a acent the June tion of said onduit an m Ql prising a rotating mold, a rotati thrown impuritinuing their rotation, whereby impurities -1 collected by said trap will be thrown out wardly by centrifugal action, and a guard partially surrounding the junction between said conduit and'casm 22. Centrifugal casting apparatus comprising a rotating mold, a rotatin' conduit means for feeding molten or liqui material to said conduit, and means for passing a gas through said conduit and into said mold.

23. Centrifugal casting apparatus comprising a rotating mold, a rotating'oonduit, a member forming a trap provided with a longitudinal passa ad'acent the junction of said conduit an mol molten or liquid material into said conduit around said member, and into the mold, and

means for assinga gas 'into said conduit and throug said passage into the mold should the passage around said member be closed.

24. Centrifugal casting apparatus commeans for passing prising a rotating mold, a rotating conduit whose mterior surface; forms a path con verging in one direction, means for passing molten material through said conduit in sai one direction, and means in the re bu of said converging pa of the con iiit' for preltt'lenting passage 0 impurities into said mo 25. Centrifugal casting apparatus ,oom-

conduit whose interior surface forms alpat diverging and then converging in one direction, means for p i .molten'm'aterial through said conduit in said one direction, and means 7 in the region of said diverging-converging passage 0 the conduit for preventing passage of impurities into said mold. Y 26. Centrifugal casting apparatus comprising a rotating mold, a rotating conduit in axial alignment therewith, means for passi molten material through said conduit and in 0 said mold, the path traversed by sa d material converging in the direction offlow in the re on of uncture of said conduit and mold-ang e. trap in said-region for prevenh ing7 of impurities into said mold.

.Cenri apparatus-comprisinga rotating mold, a rotating conduit in axial alignment therewith, means for passmolten material through said conduit :3 into said mold, the path by P 'l sa ing m the Man of ion flow in the region of juncture of said conduit and mold, and a trap having a passage communicating with said mold and conduit for preventing passage of impurities into said mold.

28. Centrifugal casting apparatus comprising a rotating mold, a rotating conduit in axial alignment therewith, means for passing molten material through said conduit and into said mold, the path traversed by said material diverging and then'converging in the direction of flow in the region of juncture of said conduit and mold, and a, trap in said region for preventing passage of im- 15 6 Wuamu- U. (/1160) y flow in the region of juncture of said conduit and mold, and a trap having a passage communicating with said mold and conduit Patent No. 1,636,228.

Itis hereby numbered patent mold strike out t same ma Signed Certificate of Correction.

ARTHUR W. GRAY.- certified that. error appears in the printed specification of the abovein'said region for preventing passage of impurities into said mold.

29. Centrifugal casting apparatus comprising a rotating mold, a rotating conduit in axial alignment therewith, means for passing molten material through said conduit and into said mold, the path traversed by said material diverging and then converging in the direction of flow in the region of juncture of said conduit and mold, and a trap having a passage communicating with said mold and conduit for preventing passage of impurities into said mold.

ARTHUR W. GRAY.

Granted July 19, 1927, to

uiring correction as=follows: Page 4, line 52, after the word e comma and insert a period same page, line 76, strike out the article a, and line 126, after the word molten that the said Letters Patent should be read with these insert the word metal; and corrections therein that the conform to the record of the case in the Patent Oflice. and sealed this 16th day of; August, A. D. 1927.

. f, M. J. MOORE, --Aatw'/ng Commissioner of Patents.

Certifieate of Correction.

A ARTHUR WV. GRAY.

It is hereby certified that error appears in the printed specification of the above numbered patent re uiring correction as folldws: Page 4, line 52, after the word mold strike out t e comma and insert a-period; same page, line 76, strike out the article a and line 126, after the word molten insert the word metal; and that the said Letters Patent should be read with these vorrections therein that the same ma conform to the record of the case the Patent Office.

Signe and sealed this 16th day of August, A. D. 1927 -1 M. J. MOORE,

Acting Coflmm'aaiorwr of Patents.

Patent No. 1,636,228. Granted July 19, 1927, to 

